1. Field of the Invention
The present invention relates to a method for producing a component, in particular a blade for a gas turbine, which comprises a main body onto which a running-in layer is applied, which is worn away at least partially during operation to form an accurately fitting surface, as well as a corresponding component, in particular a compressor blade or turbine blade for a jet turbine.
2. Prior Art
In gas turbines and particularly jet turbines, different components that must be disposed relative to one another in a very accurate fit in order to assure a high efficiency of the engine and to avoid losses are utilized both in the compressor region as well as in the turbine region. For example, care must be taken that the blades used in the compressor region and in the turbine region optimally receive flow, so that losses of efficiency do not occur due to gaps and free spaces resulting from defective fitting. This applies to rotating blades that move opposite linings or sheath rings, for example called shrouds, of the gas turbine housing, or also for stationary guide vanes opposite moving rotors that are disposed adjacent thereto.
For this purpose, so-called run-in coatings or running-in layers are known, which are worn away at least partially during operation in order to establish an accurately fitting surface. For example, in the case of guide vanes, the vane tips can abut a shroud of an adjacent rotor, whereby an accurately fitting arrangement of the guide vane tips relative to the rotor will be present during operation.
To produce running-in layers, thermal spraying methods are usually used, since the layers produced thereby already have a certain porosity and thus possess a correspondingly low strength or resistance to rubbing off or wear. Also, the porosity can be adjusted correspondingly by additional measures, as is described, for example, in JP 59 22 2 566 A. It is disclosed in this document that an NiCrAlY layer is thermally sprayed with a powder of organic material, so that with a correspondingly high temperature, the organic material will be vaporized and a porous layer will be produced.
Of course, thermally sprayed layers have limitations with respect to materials that can be used, since a high chemical reactivity is given to the particles being coated due to the high temperatures used.
Additional measures, such as introducing organic material to produce pores, also lead to considerable expenditure.